Balancing machine



1966 F. H. RUED ETAL 3,250,132

BALANC ING MACHINE Filed April 12, 1963 5 Sheets-Sheet 1 v F x INVENTOR5 F950 21/50 24) M aiccw/ 4% gWa y 1966 F. H. RUED ETAL 3,250,132

BALANCING MACHINE Filed April 12, 1963 5 Sheets-Sheet 2 INVENTOR5 F950 m 20:0

y 1966 F. H. RUED ETAL 3,250,132

BALANCING MACHINE Filed April 12, 1963 5 Sheets-Sheet 5 I I I I l I I I I I J 6 INVENTOR5 FFFO h P050 24y M. 34:00

y 1956 F. H. RUED ETAL 3,250,132

BALANCING MACHINE Filed April 12, 1965 5 Sheets-Sheet 5 lNVENTORi Fit-'0 H PUED Y Fir/w, fllccfi/ United States Patent O 3,250,132 BALANCING MACHINE Fred H. Rued, Lafayette, and Ray M. Bacchi, San Bruno,

Calif., assignors, by mesne assignments, to Baldwin- 'Lima-Hamilton Corporation, Philadelphia, Pa., a corporation of Delaware Filed Apr. 12, 1963, Ser. No. 272,655 3 Claims. (Cl. 73460) Our invention relates to devices for use in connection with the balancing of relatively large objects such as ships propellers, impellers for hydraulic turbines, and the like, of considerable bulk and having a weight of the order of one hundred thousand pounds. A balancer of this sort is shown in Patent No. 2,940,315 issued to Rued on June 14, 1960 and entitled Turbine Wheel Balancer and also shown in Patent No. 3,043,146 is sued to Rued on July 10, 1962 and entitled Weight Adjuster for a Balancer. In the construction and oper-' ation of a large balancer, there are a number of requirements which do not ordinarily appear in balancers for relatively small forces and for relatively small devices. With a large balancer for large objects the matter of friction in the balancer itself poses a substantial problem. The parts are quite large and hearings or supports to take the imposed loads have necessarily relatively high friction. This militates against careful balancing. When the object to be balanced is to rotate around. a vertical axis, it must be handled with cranes and comparable machinery, so that the space over the object must be free and clear. The object itself may have a relatively high center of gravity and be in unstable equilibrium on a subjacent support.

It is therefore an object of our invention to provide a balancer in which friction is substantially reduced over previous practice. I

Another object of the invention is to provide a balancer in which the effective point of support of the obweight and are unwieldy can be appropriately handled and mounted.

A stillfurther object of the invention is to provide a balancing machine which for its size and effectiveness is relatively inexpensive.

Other objects together with the foregoing are attained in the embodiment of the invention described in the accompanying description and illustrated in the accompanying drawings, in which:

FIGURE 1 is a side elevation of a balancer constructed in accordance with our invention;

FIGURE 2 is a plan of a balancer constructed pursuant to the invention;

FIGURE 3 is a view to an enlarged scale showing some of the-interior parts of the balancer in side elevation as seen with the covering removed;

FIGURE 4 is a cross section, the plane of which is indicated by the line 4-4 of FIGURE 3;

FIGURE 5 is a detailed plan illustrating in cross section a part of the sensing mechanism, the plane of the section being indicated by the line 55 of FIGURE 4;

. FIGURE 6 is a plan of a part of the stabilizing mechanism, the plane of section being indicated by the line 66 of FIGURE 4;,

FIGURE 7 is a fragmentary view to illustrate the relationship of certain electrical switches and their actuators; and

FIGURE 8 is a fragmentary cross section, the plane of which is indicated by the line 88 in FIGURE 3.

While the balancing machine of the invention can be embodied in a number of different ways, it has successfully been embodied as shown herein for the balancing of objects of approximately one hundred thousand pounds in weight and having substantial bulk and compass. In this form of the device, there is provided a frame 4. The frame is a metal fabrication or casting mounted on a base plate 5 also of metal appropriately supported and levelled. The frame 4 is preferably of rectangular configuration, having at least two opposite sides 6 and 7 arranged in the configuration of a truncated pyramid and partly closed by a top plate 8. The opposite side walls 6 and 7 adjacent their lower ends are formed with apertures 9 and 11, while the top plate is formed with a central opening 12.

Disposed within the frame and adapted to extend above and below the top 8 thereof is a housing 14 of generally circular cylindrical form. The housing 14 adjacent its lower end is provided with a body 16 having a pair of arms 17 and 18 extending substantially laterally or radially to and substantially through the apertures 9 and 1'1. The body 16 is removably held in position. At its upper end it abuts a flange 19 integral with the housing 14 and at its lower end is pressed into position by a ring21 held by bolts 22. A key 23 precludes relative rotation betwen the body 16 and the housing 14.

Particularly pursuant to our invention, the body 16 at the extremities-of the arms 17 and 18 carries similar blocks 27 and 28. The block 27, for example, has a bevelled face 29 against which rests the lower end of a fiexure plate 31 provided with suitable apertures to receive through bolts 32 fastened by nuts 33 bearing against a securing block 34. In this fashion the lower end of the fiexure plate 31 is firmly related to the housing 14 at one extremity of the arm 17. A symmetrical arrangement is provided for the arm 18 and a companion fiexure plate 36.

The inclination of the bevelled faces 29 and the corresponding inclination of the fiexure plates 31 and 36 are such that the planes of the plates intersect substantiallyv at a location considerably above the top of the mechanical structure and preferably so as to coincide substantially or exactly with the center of gravity of a body to be balanced. 'I he fiexure plates 31 and 36 are of ferrous material and of rectangular proportions. They are located opposite each other on the frame 4 and extend from the point of attachment at the end of the arms 17 and 18 to points above the top plate 8. At the upper end of each of the two fiexure plates 31 and 36 are bolts 40.

appropriate fastenings 37 in the nature of bolts passing through securing blocks 38 and through apertures in the upper ends of the fiexure plates and being lodged in mounting blocks 39 fastened to the top plate 8 by Since the fiexure plates 31 and 36 are relatively yieldable, the housing 14 can move relative to the frame 4 in a lateral or transverse direction. That is tosay, there can be relative sidewise movement in a vertical plane between the housing 14 in relation to the frame 4 with the arms 17 and 18 moving toward and away from the opposite sides 6 and 7'of the frame 4.

Disposed within the housing 14 is a shaft 41 adjacent its upper end mounted in a bearing 42, preferably a spherical ball bearing, and at its lower end mounted in a radial ball bearing 43 so that the shaft 41 is rotatable relative to the housing 14 about an axis 44 which is sub stantially upright or vertical, although subject to' slight lateral excursions.

At the upper end of the shaft 41 there is a mounting table 46 having a central hub 47 and designed for the reception of an object to be balanced, with the center line of rotation of the object substantially coincident with the axis 44.

Power means are provided for rotating the shaft 41 relative to the housing 14 about the axis 44. Secured to i brackets 51 and 52 extending from the housing 14 is an electric motor 52 arranged with its driving shaft vertical and connecting through a reduction gear and variable speed mechanism 54 to a helical drive pinion 56. This meshes with a helical driven gear 57 secured by fastenings 58 to the underside of the table 46. The electrical connections to the motor 53 (not shown) are by means of flexible cables so that the motor 53 can move bodily with the housing 14 and relative to the frame 4 without hindrance. When the motor 53 is energized, the gear 57 and the central shaft 41 are rotated and the object being balanced is rotated in unison therewith.

Connected to the table 46 is a rotary framework 61 made up of appropriate structural plates and shapes and carrying certain radially extending balance arms pursuant to the above-mentioned Rued patent. Disposed in quadrature as seen in plan and extending from the periphery of the framework 61 are two dynamic balance arms 62 and 63. Similarly disposed in quadrature when seen in plan not only with respect to each other, but also with respect to the arms 62 and 63, are static balancing arms 64 and 66.

Each of the static balance arms has a movable weight 67 mounted thereon for rectilinear translation under the drive of a helical screw 68 propelled by an electric motor 69. Somewhat similarly, each of the dynamic balance arms has arranged thereon a vertically movable weight 71 constrained to rectilinear translation, and propelled by a helical screw 72 driven by an electric motor 73. The various power and control wires for driving the sundry motors are brought in through the various arms and are passed through the hollow interior of the shaft 41 to a slip ring assembly 74. This is disposed at the bottom of the shaft 41 and has a stationary member 76 secured to the bottom of the housing 14. The electrical circuits are thus completed through the slip ring assembly from a control station not shown) to the various electric motors. Mounted on the various arms are scales 77 and 78 for visual indication of the position of the weights 67 and 71.

When an unbalanced body is on the table 46 or before the balancer itself has been put into appropriate balance, operation of the electric motor 53 rotates the unbalanced parts and produces a transverse oscillation or a relative transverse movement between the housing 14 and the frame 4. Means are provided for responding to such transverse relative movement. Upstanding from the base plate is a bracket 81 having a central thimble 82 defining a passage through which a transfer rod 83 extends. At one end the transfer rod is hollow to receive an elastomeric O-ring 84 also engaged with an adjusting screw 86 having a lock nut 87. Engaged by the screw 86 is a screw block 88 depending from the block 27 at the extremity of the transverse arm 17. Thus, movement of the arm is transmitted directly to and is shared by the rod 83. The rod 83 is supported in the thimble 82 by a similar elastorneric O-ring 89 so that the rod 83 is yieldingly or resiliently restrained in transvere directions, but since the adjusting screw 86 abuts against the end of the rod 83, there is a direct transmission of axial force.

The extreme end of the rod 83 is narrowed to abut against a sensing beam 91. This is preferably a specially shaped and contoured member to one face of which a pair of strain gauges is afiixed and to the opposite face of which another pair of strain gauges is affixed. The strain gauges are connected to appropriate indicating mechanism. The gauges and electrical connections are as shown in the above-mentioned Rued patent. Conveniently, the beam 91 and the strain gauges are encapsulated in an elastorneric material. The ends of the beam are set against shoulders 92 and 93 in a yoke 94. Passing through the yoke are adjusting bolts 96 and 97 which also pass through the bracket 81. Adjusting nuts 99 govern the relative position of the parts. Similar adjusting nuts 101 adjust the relationship of the rods 96 and 97 with coil springs 102 and 103 also abutting the bracket 81. The arrangement is such that normally the yoke 94 is urged against spacers 104 and 105 resting on the bracket 81 to hold the shoulders 92 and 93 in precise relationship with the bracket 81. Thus whenever the housing 14 moves transversely, the block 88 is similarly moved and through the rod 83 produces a comparable flexure of the beam 91.

Normally, the beam is flexed to one extreme when the housing 14 is in a similar extreme position, but to prevent damage the tension in the springs 102 and 103 is such that if there is an excessive force or movement toward the right in FIGURE 5 the springs yield and the beam 91 is not unduly flexed. When the extra force ceases, the springs 102 and 103 return the parts to their normal relationship.

To complement the responsive mechanism, including the beam 91, the base 5 is also provided with an upright bracket 106 carrying a shoulder bolt 187 fastened by a nut 10% and serving as the mounting for a helical spring 109. Also abutting the spring 109 is a washer 111 at the end of an adjusting screw 112 fixed by a lock nut 113 in a block 114 depending from the anchor block 28 at the extremity of the arm 18. The adjustment of the screw 112 is such that a preload is put on the spring 109 so as to centralize the mechanism under balance conditions. The amount of relative movement laterally between the housing 14 and the frame 4 is limited by providing at both extremities of both of the blocks 34 certain adjusting screws 121 (FIGURE 8) passing through the intervening space and adapted to have a clearance of a predetermined amount (in one instance, .030 inch) with the subjacent portion of the frame 4. While the housing 14 is free to oscillate in a vertical plane in response to unbalanced forces, the amount of excursion of the housing relative to the frame is distinctly limited to avoid injury to the various responsive parts.

To assist in the operation of the indicating mechanism, particularly to assist in reading the meter which responds to amplified currents from the various strain gauges on the beam 91, the housing 14 has a pair of small electrical switches 131 and 132 on one side and a comparable pair of electrical switches 133 and 134 at a different radius on the other side. Since impulses or indications are desired at each ninety degrees of rotation of the shaft 41, the underside of the gear 57 (FIGURE 3) is provided with appropriate pairs (FIGURE 7) of flexible cam actuators 135. Each of the flexible actuators 135 is subject to ad justment by a set screw 136 to afford the appropriate amount and time of contact with the associated switch. The switches are disposed on the same diameter and are also arranged at different radial distances from the axis 44. The quadrant actuators 135, being also spaced at different radial distances, afford one closure of each switch for each revolution, the intervals of closure between the various switches being equivalent to successive ninety degree rotations of the shaft 41 or the table 46.

The details of the indicating mechanism responsive to the strain gauges on the beam 91 are not shown herein, but are comparable to those in the Rued patent. In the operation of the present device, the motor 53 is first energized before any object to be balanced is placed on the table 46. The balancer aloneis rotated at an appropriate speed to determine any unbalance in the balancer itself. This is suitably indicated and the operator energizes the various motors 73 on the radial arms to position the various weights 67 and 71 to afford as nearly as may be a proper static and dynamic balance of the balancer itself. It is the custom in large balancers of this sort to refer to a static balance as one producing substantially no oscillation or relative movement of the housing 14 relative to the frame 4 when the turntable 46 is revolving at approximately one revolution per minute. It is also the custom to refer to a dynamic balance as one which produces substantially no displacement or oscillation of the housing 14 relative to the frame 4 when the table 46 revolves at a higher rate of speed, say, from thirty to forty revolutions per minute. Following the balancing of the balancer itself, an ob ject to be balanced is then mounted on the turntable 46 when it is stationary. The rotational axis of the body is arranged to be substantially coincident with the axis 44. The center of gravity of the object to be balanced normally is at a point substantially above the table 46 and preferably at a point near the intersection of the planes of the fiexure plates 31 and 36. Following the positioning of the object to be balanced, the motor 53 is energized to rotate the table 46 and the object substantially at one revolution per minute. The various switches 131, 132, 133 and 134 are successively actuated to provide appropriate reading indications of a meter which responds to impulses from the strain gauges on the beam 91. Since the beam 91 has a deflection or fiexure pursuant to the amount of displacement produced by the unbalance of the object being balanced, this indication is then read at the proper intervals as set forth in the above-mentioned patent of Rued.

Depending upon such indications, the operator then controls the circuits effective through the slip ring assembly 74 to energize and deenergize the various motors 73 to arrange a substantially exact static balance by changing the position of the weights 67 correspondingly on the arms 64 and 66. When this has been properly accomplished, the motor 53 is energized to drive the turntable 46 at the higher rate of speed, say, thirty to forty revolutions per minute, and similar indications and readings are made.

The operator further controls the motors 73 for the weights 71, moving such weights until there is a satisfactory dynamic balance. Following this, from a reading of the position of the various static and dynamic weights, a calculation of the appropriate weight to be added or removed to put the object in balance is made.

What is claimed is:

1. A balancing machine comprising a frame, a housing, a substantially vertical shaft, means for mounting said shaft in said housing for rotation about a substantially vertical axis, a first planar fiexure plate extending substantially vertically, means for connecting the upper end -of said first flexure plate to said frame on one side of said axis, means for connecting the lower end of said first flexure plate to said housing on said one side of said axis, a second planar fiexure plate extending substantially vertically, :means for connecting the upper end of said second flexure plate to said frame on the opposite side of said axis, means for connecting the lower end of said second flexure plate to said housing on said opposite side of said axis, all of said connecting means disposing both of said fiexure plate to lie in planes normal to a plane containing said axis, means for rotating said shaft, means for supporting an object to be balanced on said shaft, means interposed between said frame and said housing and responsive to relative movement thereof, and said plates being on diametrically opposite sides of said axis and lying in converging planes which intersect at said axis immediately above and adjacent said supporting means.

2. A balancing machine comprising a frame having a top with an opening therein and having opposite sides with apertures therein, a housing extending through said opening, planar fiexure platesfacing each other and disposed on diametrically opposite sides of said housing, means for securing the upper ends of said flexure plates to the outside of said frame adjacent said top, means on the bottom of said housing extending transversely through said apertures, means for securing the lower ends of said flexure plates to said extending means at locations outside said housing, a shaft mounted in said housing for rotation therein about a substantially vertical axis, means on said shaft above said housing for supporting an object to be balanced, means responsive to movement of said housing relative to said frame toward and away from said opposite sides, and said plates lying in converging planes which intersect at said axis above said supporting means at a location adapted to substantially coincide with the center of gravity of a body to be balanced.

3. A balancing machine comprising a frame having opposite sides, a pair of ilexure plates, means for securing each of said fiexure plates at one end thereof to a respective one of said opposite sides of said frame, a housing having opposite sides, means for securing each of said flexure plates at the other end thereof to a respective one of the opposite sides of said housing, all of said securing means disposing both of said flexure plates to be in planes normal to a plane containing said axis, means responsive to movement of said housing toward and away from said opposite sides of said frame, a shaft journalled in said housing, means on said shaft for supporting an object to be balanced, and said plates being on diametrically oppo'site sides of said housing, said plates lying in converging planes which intersect above and adjacent said supporting means at a line which is adapted to be located substantially at the center of gravity of a body to be balanced.

References Cited by the Examiner UNITED STATES PATENTS 1,364,994 1/ 1921 Johnson 73-470 1,515,350 11/ 1924 Lundgren 73-470 1,540,643 6/1925 Lundgren 73-470 2,817,972 12/1957 Bokorney 73-471 2,891,241 6/ 1959 Fibikar 73-462 X 2,940,315 6/ 1960 Rued 73-467 2,986,920 6/ 1961 Fibikar 73-462 3,034,361 5/1962 Karpchuk 73-471 3,03 7,403 6/1962 Hack et a1 73-463 X 3,124,005 10/1964 White 73-471 FOREIGN PATENTS 867,872 5/1961 Great Britain.

RICHARD C. QUEISSER, Primary Examiner. JAMES J. GILL, Examiner. 

1. A BALANCING MACHINE COMPRISING A FRAME, A HOUSING A SUBSTANTIALLY VERTICAL SHAFT, MEANS FOR MOUNTING SAID SHAFT IN SAID HOUSING FOR ROTATION ABOUT A SUBSTANTIALLY VERTICAL AXIS, A FIRST PLANAR FLEXURE PLATE EXTENDING SUBSTANTIALLY VERTICALLY, MEANS FOR CONNECTING THE UPPER END OF SAID FIRST FLEXURE PLATE TO SAID FRAME ON ONE SIDE OF SAID AXIS, MEANS FOR CONNECTING THE LOWER END OF SAID FIRST FLEXURE PLATE TO SAID HOUSING ON SAID ONE SIDE OF SAID AXIS, A SECOND PLANAR FLEXURE PLATE EXTENDING SUBSTANTIALLY VERTICALLY, MEANS FOR CONNECTING THE UPPER END OF SAID SECOND FLEXURE PLATE TO SAID FRAME ON THE OPPOSITE SIDE OF SAID AXIS, MEANS FOR CONNECTING THE LOWER END OF SAID SECOND 